There is a rapidly expanding demand in a variety of different markets, such as in electronic consumer products, electronics locks, and medical devices, for motors that can move tiny optics and other devices with sub-micrometer precision. By way of example, in the electronic consumer products market, the size of mobile phone handsets continues to shrink while the demand for the inclusion of features, such as digital cameras, in the mobile phone handsets continues to grow. To cost effectively add a digital camera feature into these mobile phones, the digital cameras need to be about one tenth the volume and cost of stand alone digital cameras. Unfortunately, existing solutions for trying to meet these radical size and cost reduction requirements in digital cameras have been less than successful.
Some prior mobile phone handsets with digital cameras have used fixed optics. Unfortunately, these fixed optics do not meet most consumer expectations for adjustable focusing capabilities in digital cameras in mobile phone handsets.
Other prior mobile phone handsets have used miniaturized electromagnetic motors with their digital cameras to provide adjustable focusing capabilities, e.g. the ability to move a lens up to about 0.5 millimeters. In particular, voice coil motors are popular for use as the miniaturized electromagnetic motors in these digital cameras in the mobile phone sets. Voice coil motors are simple, inexpensive, and operate at relatively low voltage.
However, voice coil motors have reached the limit of their potential miniaturization and can not satisfy the emerging market demand for ultra-thin phones with more than two mega pixels image sensors. Additionally, even though these voice coil motors operate at relatively low voltage, they still use too much power. Further, these voice coil motors must be supported by fragile flexure guides and produce excessive position noise for optimal image capture when using two mega pixels or higher digital image sensors.